drm/apple: Support color transformation matrices

kwin 5.27.3 adds support for "Night Color" via drm "CTM" properties.
Wire CTM support up via the "set_matrix" iomfb call.

Link: https://bugs.kde.org/show_bug.cgi?id=455720
Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/apple_drv.c

@@ -334,6 +334,7 @@ static int apple_probe_per_dcp(struct device *dev,
 		return ret;
 
 	drm_crtc_helper_add(&crtc->base, &apple_crtc_helper_funcs);
+	drm_crtc_enable_color_mgmt(&crtc->base, 0, true, 0);
 
 	enc = drmm_simple_encoder_alloc(drm, struct apple_encoder, base,
 					DRM_MODE_ENCODER_TMDS);

drivers/gpu/drm/apple/iomfb.h

@@ -160,6 +160,7 @@ enum dcpep_method {
 	iomfbep_a358_vi_set_temperature_hint,
 	iomfbep_get_color_remap_mode,
 	iomfbep_last_client_close,
+	iomfbep_set_matrix,
 	dcpep_num_methods
 };
 
@@ -350,4 +351,17 @@ struct iomfb_last_client_close_resp {
 	u32 unkint;
 } __packed;
 
+struct iomfb_set_matrix_req {
+	u32 unk_u32; // maybe length?
+	u64 r[3];
+	u64 g[3];
+	u64 b[3];
+	u8 matrix_null;
+	u8 padding[3];
+} __packed;
+
+struct iomfb_set_matrix_resp {
+	u32 ret;
+} __packed;
+
 #endif

drivers/gpu/drm/apple/iomfb_template.c

@@ -55,6 +55,7 @@ DCP_THUNK_OUT(iomfb_a131_pmu_service_matched, iomfbep_a131_pmu_service_matched,
 DCP_THUNK_OUT(iomfb_a132_backlight_service_matched, iomfbep_a132_backlight_service_matched, u32);
 DCP_THUNK_OUT(iomfb_a358_vi_set_temperature_hint, iomfbep_a358_vi_set_temperature_hint, u32);
 
+IOMFB_THUNK_INOUT(set_matrix);
 IOMFB_THUNK_INOUT(get_color_remap_mode);
 IOMFB_THUNK_INOUT(last_client_close);
 
@@ -1285,7 +1286,24 @@ void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, stru
 		dcp->brightness.update = false;
 	}
 
-	do_swap(dcp, NULL, NULL);
+	if (crtc_state->color_mgmt_changed && crtc_state->ctm) {
+		struct iomfb_set_matrix_req mat;
+		struct drm_color_ctm *ctm = (struct drm_color_ctm *)crtc_state->ctm->data;
+
+		mat.unk_u32 = 9;
+		mat.r[0] = ctm->matrix[0];
+		mat.r[1] = ctm->matrix[1];
+		mat.r[2] = ctm->matrix[2];
+		mat.g[0] = ctm->matrix[3];
+		mat.g[1] = ctm->matrix[4];
+		mat.g[2] = ctm->matrix[5];
+		mat.b[0] = ctm->matrix[6];
+		mat.b[1] = ctm->matrix[7];
+		mat.b[2] = ctm->matrix[8];
+
+		iomfb_set_matrix(dcp, false, &mat, do_swap, NULL);
+	} else
+		do_swap(dcp, NULL, NULL);
 }
 
 static void res_is_main_display(struct apple_dcp *dcp, void *out, void *cookie)

drivers/gpu/drm/apple/iomfb_v12_3.c

@@ -18,6 +18,7 @@ static const struct dcp_method_entry dcp_methods[dcpep_num_methods] = {
 	IOMFB_METHOD("A410", dcpep_set_display_device),
 	IOMFB_METHOD("A411", dcpep_is_main_display),
 	IOMFB_METHOD("A412", dcpep_set_digital_out_mode),
+	IOMFB_METHOD("A422", iomfbep_set_matrix),
 	IOMFB_METHOD("A426", iomfbep_get_color_remap_mode),
 	IOMFB_METHOD("A439", dcpep_set_parameter_dcp),
 	IOMFB_METHOD("A443", dcpep_create_default_fb),

drivers/gpu/drm/apple/iomfb_v13_2.c

@@ -18,6 +18,7 @@ static const struct dcp_method_entry dcp_methods[dcpep_num_methods] = {
 	IOMFB_METHOD("A410", dcpep_set_display_device),
 	IOMFB_METHOD("A411", dcpep_is_main_display),
 	IOMFB_METHOD("A412", dcpep_set_digital_out_mode),
+	IOMFB_METHOD("A422", iomfbep_set_matrix),
 	IOMFB_METHOD("A426", iomfbep_get_color_remap_mode),
 	IOMFB_METHOD("A441", dcpep_set_parameter_dcp),
 	IOMFB_METHOD("A445", dcpep_create_default_fb),